Explosion proof centrifugal fan is mainly composed of explosion-proof fan body and explosion-proof motor. The explosion-proof fan body includes casing, impeller, transmission group and integral steel frame. When the casing is made of steel, the impeller must be made of I cast aluminum. The first version of explosion-proof motor is a three-phase asynchronous motor with voltage of 380 / 660V, explosion-proof grade: ExdIIBT4 or exdiict4. The installation mode of explosion-proof motor is generally B3 or B35 horizontal installation, After understanding the basic structure of the fan, let's talk about how to select the explosion-proof centrifugal fan.
Firstly, the definition of explosion-proof equipment is that it will not cause the ignition of the surrounding explosive environment under the specified conditions. The design of explosion-proof centrifugal fan naturally follows this basic principle, but it should be noted that in addition to preventing the ignition of explosive environment, the explosion-proof centrifugal fan should also prevent the ignition of explosive media, that is, the explosion-proof centrifugal fan should also prevent the ignition of explosive gas transported by explosion-proof centrifugal fan. Therefore, the core of explosion-proof centrifugal fan is to use components to avoid sparks. It mainly includes two points: explosion-proof motor and aluminum impeller.
Secondly, there are explosion-proof grades and national standards on the Internet, so I won't repeat them.
It should be noted that the explosion-proof is relative and does not include extreme cases. For example, there is no spark in the explosion-proof motor, but the overload of the motor may lead to open fire in the cable, and there will be no spark when the aluminum impeller rubs with the casing, but there will still be sparks if there are metal foreign matters entering the casing and colliding. I have consulted the technicians of Yifeng fan. Some professionals have demonstrated that in some special cases, the fan with copper impeller may produce sparks
In addition, stainless steel is not explosion-proof, although the carbon content is low.
